Optically Rewritable Memory in a Graphene–Ferroelectric-Photovoltaic Heterostructure

Achieving optical operation of logic elements, especially those that involve two-dimensional (2D) layers, could kick-start the long-awaited era of optical computing. However, efficient optical modulation of the electronic properties of 2D materials, including the rewritable memory effect, is currently lacking. Here we report all-optical control of the conductivity of graphene with write-erase operation yet under ultralow optical fluence. The competition between light-induced charge generation in a ferroelectric-photovoltaic substrate and relaxation processes provides the selective photocarrier-trapping control affecting the doping of the 2D overlayer. These findings open the way to photonic control of 2D devices for all-optical modulators, a variety of all-optical logic circuits, memories, and field-effect transistors.